TWI390592B - Method and apparatus for ashing a substrate using carbon dioxide - Google Patents

Description

Method and apparatus for utilizing carbon dioxide for substrate ashing

The present invention relates to a method and apparatus for removing residue from a substrate.

During semiconductor processing, a (dry) plasma etch process can be used to remove or etch away material along the fine lines or material in the via holes or contact holes patterned over the germanium substrate. Plasma etching processes typically involve the use of a fully covered patterned protective layer, such as a photoresist layer, to position the semiconductor substrate within the processing chamber. Once the substrate is positioned in the processing chamber, an ionizable and separated gas mixture having a predetermined flow rate is immediately introduced into the processing chamber while the vacuum pump is throttled to achieve atmospheric processing pressure. Thereafter, when a certain proportion of the gas species present is ionized by the heated electrons, the plasma is formed, wherein the electrons are heated by transfer of inductive or capacitive radio frequency (RF) power, or microwave power is utilized. And heating, for example, an electron cyclotron resonator (ECR). Again, the heated electrons are used to separate certain species of the gaseous species of the atmosphere and produce reactive species suitable for the etch chemistry that exposes the surface. Once the plasma is formed, the selected surface on the substrate is etched using the plasma. The process is adjusted to the appropriate conditions, including the appropriate concentration of the desired reactants and the amount of ions used to etch various features (e.g., trenches, vias, contact holes, etc.) in selected regions of the substrate. Such a substrate material that can be etched must be cerium oxide (SiO ₂ ), a low dielectric constant (ie, low-k) dielectric material, polycrystalline germanium, and tantalum nitride. Once the pattern is transferred from the patterned photoresist layer to the underlying dielectric layer using, for example, dry plasma etching, the remaining photoresist layer and post-etch residue can be removed by ashing (or stripping) processing. For example, in a conventional ashing process, a substrate having a residual photoresist layer is exposed to an oxygen plasma, and the oxygen plasma is formed by introduction of diatomic oxygen (O ₂ ) and ionization/separation thereof.

The present invention relates to a method of removing residues on a substrate by plasma ashing. The plasma ashing process utilizes a process gas comprising carbon dioxide. In addition, The process gas may comprise a passivating gas such as a hydrocarbon gas.

In accordance with an embodiment, a method of removing residue from a substrate and a computer readable medium having program instructions for causing a computer system to control residue removal processing includes: arranging the substrate in a plasma processing system The substrate has a dielectric layer formed thereon and a mask layer covering the dielectric layer, wherein the mask layer comprises a pattern formed in one of the mask layers, and The pattern is transferred to an etching process of the dielectric layer, the dielectric layer comprising a pattern formed therein; a process gas containing one of carbon dioxide (CO ₂ ) is introduced; in the plasma processing system, from the process gas Forming a plasma; and removing the mask layer from the substrate using the plasma.

According to another embodiment, a plasma processing system for removing photoresist from a substrate is provided, comprising: a plasma processing chamber for promoting a process gas to form a plasma; and a controller coupled to the plasma The processing chamber is configured to perform a processing recipe that utilizes the processing gas to form a plasma to remove the photoresist from the substrate, wherein the processing gas comprises carbon dioxide (CO ₂ ).

In the following description, specific details are set forth for purposes of explanation and not limitation, such as specific geometric features of the plasma processing system and description of various processes. However, it is to be understood that the invention may be practiced in other embodiments of the specific details described above.

In the material processing method, the pattern etching comprises coating a thin layer of photosensitive material, such as a photoresist, on the upper surface of the substrate, and then patterning the photoresist, which can be used on the substrate to transfer the pattern to the bottom during etching. The mask of the film. Patterning of the photosensitive material typically involves exposing the photosensitive material to a geometric pattern of electromagnetic (EM) radiation using, for example, a microlithography system, followed by removal of the photosensitive material of the illuminated area using a developing solvent (in the case of a positive photoresist), Or a photosensitive material in the non-irradiated area (in the case of a negative photoresist). Additionally, the mask layer can include multiple sublayers.

For example, as shown in FIGS. 1A to 1C, a photosensitive layer containing the pattern 2 can be utilized. A mask of 3 (such as a patterned photoresist) for transferring the feature pattern to the film 4 on the substrate 5. The pattern 2 can be formed by transferring the pattern 2 to the film 4 by, for example, dry plasma etching. The mask 3 is removed immediately after the etching is completed.

As mentioned above, the mask can be removed by exposing the mask to a plasma formed by the O ₂ -containing gas. However, the inventors have recognized that this method can damage dielectric films, particularly low-k dielectric films. Damage such as this can affect the critical dimension of the etched features in the dielectric or can increase the dielectric constant of the dielectric. The inventors have further recognized that carbon can make the dielectric and low-k film less susceptible to chemical changes, and can minimize damage to such films. Thus, in one embodiment, be removed by using the mask 3 (CO ₂₎ of the process gas comprises carbon dioxide. The use of CO ₂ reduces damage to the dielectric compared to the O ₂ plasma etch process. In another embodiment, it comprises using a carbon dioxide (CO ₂₎ gas and a passivation process to remove the gas mask 3. For example, the passivation gas may comprise a hydrocarbon gas (C _x H _y ), wherein x, y represents an integer greater than or equal to one. The hydrocarbon gas (C _x H _y ) may comprise more than one of C ₂ H ₄ , CH ₄ , C ₂ H ₂ , C ₂ H ₆ , C ₃ H ₄ , C ₃ H ₆ , C ₃ H ₈ , C ₄ H ₆ C ₄ H ₈ , C ₄ H ₁₀ , C ₅ H ₈ , C ₅ H ₁₀ , C ₆ H ₆ , C ₆ H ₁₀ or C ₆ H ₁₂ , or two or more of the above. Alternatively, the process gas further comprises an inert gas such as an inert gas (ie, He, Ne, Ar, Kr, Xe, Rn). Or even more, the processing gas further contains O ₂ , CO, NO, NO ₂ or N ₂ O or a combination of two or more of the above.

2 shows a plasma processing system 1 comprising: a plasma processing chamber 10; a diagnostic system 12 coupled to the plasma processing chamber 10; and a controller 14 coupled to the diagnostic system 12 and plasma processing Room 10. The controller 14 is configured to perform a treatment formulation comprising at least one of the above-identified chemical substances (ie, CO _{2 with} or without C _x H _y and/or other gases, etc.), which can remove photoresist and/or other residues from the substrate. Things, such as etching residues. In addition, the controller 14 is configured to receive at least one end point signal from the diagnostic system 12 and post-process the at least one end point signal to correctly determine the end of the process. In the illustrated embodiment, the plasma processing system 1 illustrated in Figure 2 utilizes plasma for material processing. The plasma processing system 1 includes an etch chamber and an ash chamber or a combination thereof.

According to the embodiment shown in FIG. 3, the plasma processing system 1a may comprise: a plasma station a chamber 10; a substrate holder 20 to which the substrate 25 to be processed is fixed; and a vacuum pumping system 30. The substrate 25 can be a semiconductor substrate, a wafer or a liquid crystal display panel. The plasma processing chamber 10 can be used to facilitate the generation of plasma in the processing zone 15 adjacent the surface of the substrate 25. A mixture of ionizable gas or gas is introduced via a gas injection system (not shown) and the treatment pressure is adjusted. For example, a control mechanism (not shown) may be used to throttle the vacuum pumping system 30. The plasma can be used to produce a particular material required for processing a predetermined material, and/or to help remove material from the exposed surface of the substrate 25. The plasma processing system 1a can be used to process substrates of any desired size, such as 200 mm substrates, 300 mm substrates or larger.

The substrate 25 is fixed to the substrate holder 20 by an electrostatic clamping system. Further, the substrate holder 20 further includes a cooling system including a recirculating refrigerant fluid that can absorb heat from the substrate holder 20 and transfer the heat to a heat exchanger system (not shown) or, when heated, from the heat The heat exchanger system is transferred to the substrate support 20. Further, the gas can be transferred to the back surface of the substrate 25 by the back gas system, and the heat conductivity of the gas-gap between the substrate 25 and the substrate holder 20 can be improved. Such a system can be used when temperature control of the substrate is required at elevated or lowered temperatures. For example, the backside gas system includes a two-section gas distribution system in which the air gap pressure of the helium gas can be independently varied between the center and the edge of the substrate 25. In other embodiments, the substrate support 20 and the wall of the plasma processing chamber 10 and any other component of the plasma processing system 1a may have heating/cooling elements, such as resistive heating elements, or electrothermal heaters. Cooler.

In the embodiment shown in FIG. 3, the substrate support 20 includes electrodes through which RF power can be coupled to the processing plasma in the processing space 15. For example, the RF power delivered to the substrate support 20 from the RF generator 40 through the impedance matching network 50 is such that the substrate support 20 is electrically biased at the RF voltage. The RF bias is used to heat electrons to form and maintain the plasma. In this configuration, the system operates as a reactive ion etching (RIE) reactor in which the processing chamber and the upper gas injection electrode system act as a ground plane. Typically, the frequency of the RF bias ranges from about 0.1 MHz to about 100 MHz. The RF systems required for plasma processing are well known to those skilled in the art.

Alternatively, the substrate support electrodes are subjected to RF power at a plurality of frequencies. Again, by The power of the reflection is reduced to cause the impedance matching network 50 to increase the RF power of the plasma transferred into the plasma processing chamber 10. Matching network types (e.g., L-type, π-type, T-type, etc.) and automatic control methods are well known to those skilled in the art.

Further, the plasma processing system 1a includes a gas injection system (not shown) for introducing the process gas into the processing zone 15. The gas injection system includes a showerhead gas injection system located above the substrate, which is well known to those skilled in the art of vacuum processing. Alternatively, the gas injection system comprises a multi-segment gas injection system. For example, the gas injection system includes: a first group of gas injection holes connected to a gas supply system for introducing a process gas into a substantially central region above the substrate; and a second group of gas injection holes connected to a gas supply system and used The process gas is introduced into a substantially surrounding area above the substrate.

The vacuum pumping system 30 includes a turbomolecular vacuum pump (TMP) capable of reaching a vacuum rate of about 5000 liters per second (and larger) and a gate valve for throttling the chamber pressure. In the conventional plasma processing apparatus for dry plasma etching, TMP of 1000 to 3000 liters per second is usually employed. TMPs are suitable for low pressure processing, typically below about 50 mTorr. In the case of high pressure treatment (i.e., greater than about 100 mTorr), a mechanical booster pump and a dry schematic pump are used. Further, a device (not shown) for monitoring the pressure in the processing chamber is connected to the plasma processing chamber 10. The pressure measuring device is, for example, a Model 628B Ballardon Capacitive Absolute Pressure Gauge sold by MKS Instruments, Inc. (Andwa, Maryland).

The controller 14 includes a microprocessor, a memory, and a digital I/O port that is capable of not only monitoring the output from the plasma processing system 1a, but is also capable of generating a control voltage sufficient to communicate and cause input to the plasma processing system 1a. Further, the controller 14 is connected not only to the back surface gas delivery system (not shown), the substrate/substrate pedestal temperature measurement system (not shown), and/or the electrostatic clamp system (not shown), but also exchanges information with it. It is further connected to and exchanges information with the RF generator 40, the impedance matching network 50, the gas injection system (not shown), and the vacuum pumping system 30. For example, the program stored in the memory causes the input of the aforementioned components input to the plasma processing system 1a according to the processing recipe, and the method of removing the photoresist from the substrate can be performed. An example of controller 14 is the Dell Precision Workstation 610 ^(TM) from Dell Corporation of Austin, Texas.

The controller 14 may be disposed at a site relative to the plasma processing system 1a, or may be disposed at a distal end relative to the plasma processing system 1a. For example, the controller 14 can be exchanged with the plasma processing system 1a using at least one of a direct connection, an internal network, and an internet. For example, the controller 14 is connected to the internal network at the user (and device manufacturer, etc.); or, for example, at the supplier (and device manufacturer) to connect to the internal network. Additionally, for example, controller 14 can be connected to the internet. Also, for example, another computer (i.e., controller, server, etc.) can access the controller 14 via at least one of a direct connection, an internal network, and the Internet to exchange data.

The diagnostic system 12 includes an optical diagnostic subsystem (not shown). The optical diagnostic subsystem includes a detector such as a (photo) photodiode or a photomultiplier tube (PMT) for measuring the intensity of light emitted by the plasma. The diagnostic system 12 further includes a filter, such as a narrowband interference filter. In another embodiment, the diagnostic system 12 includes at least one of a linear CCD (charge coupled device), a CID (charge injection device) array, and a beam splitting device such as a grating or a chirp. In addition, the diagnostic system 12 has a monochromator (eg, a raster/detector system) to measure light at a particular wavelength, or a beam splitter (eg, a rotary grating) to measure the spectrum, such as described in US Pat. No. 5,888,337. The device is hereby incorporated by reference in its entirety.

The diagnostic system 12 includes, for example, a high resolution emission spectroscopy (OES) sensor from a spike sensor system or Villedy Instruments. Such OES sensors have a broad spectrum across the ultraviolet (UV), visible (VIS) and near infrared (NIR) spectra. The resolution is about 1.4 angstroms, which means that the sensor is capable of collecting 5,550 wavelengths between 240 and 1000 nm. The OES sensor can be equipped with a high-sensitivity small fiber UV-VIS-NIR spectrometer and then integrated into a 2048-pixel linear CCD array.

The spectrometer receives light transmitted through a single or bundle of optical fibers, wherein the light output by the optical fibers is dispersed across a linear CCD array having a fixed grating. Similar to the above structure, light passing through the optical vacuum window is focused over the input end of the fiber via a convex spherical mirror. Three spectrometers, each adjusted for a specific spectral range (UV, VIS, and NIR), constitute the sensors required for the processing chamber. Split light The meter includes a separate A/D converter. In recent years, a complete emission spectrum can be recorded every 0.1 to 1.0 seconds depending on the purpose of the sensor.

In the embodiment shown in FIG. 4, the plasma processing system 1b is similar to the embodiment of FIG. 3 and includes, in addition to the elements described with reference to FIG. 3, a magnetic field system 60 that is fixed, or mechanically or electrically rotated,俾 can potentially increase plasma density and / or improve plasma processing consistency. In addition, the controller 14 is coupled to the magnetic field system 60 to adjust the rotational speed and magnetic field strength. The design and implementation of a rotating magnetic field is well known to those skilled in the art.

In the embodiment shown in FIG. 5, the plasma processing system 1c is similar to the embodiment of FIG. 3 or FIG. 4, and further includes an upper electrode 70, and the RF power from the RF generator 72 is via the impedance matching network 74. Connected to the upper electrode 70. The frequency of the RF power applied to the upper electrode ranges from about 0.1 MHz to about 200 MHz. Further, the frequency of the power applied to the lower electrode ranges from about 0.1 MHz to about 100 MHz. Further, the controller 14 is connected to the RF generator 72 and the impedance matching network 74 to control the RF power applied to the upper electrode 70. The design and implementation of the upper electrode is well known to those skilled in the art.

In the embodiment illustrated in FIG. 6, the plasma processing system 1d is similar to the embodiment of FIGS. 3, 4, and 5, and further includes an induction coil 80, and the RF power from the RF generator 82 is via an impedance matching network 84. Connected to the induction coil 80. The RF power from the induction coil 80 is inductively coupled to the plasma processing zone 15 via a dielectric aperture (not shown). The frequency of the RF power applied to the induction coil 80 ranges from about 10 MHz to about 100 MHz. Similarly, the frequency of the power applied to the clamp electrodes ranges from about 0.1 MHz to about 100 MHz. Additionally, a slotted Faraday barrier (not shown) may be employed to reduce the capacitive connection between the induction coil 80 and the plasma. Further, the controller 14 is coupled to the RF generator 82 and the impedance matching network 84 to control the power applied to the induction coil 80. In another embodiment, as in the case of a transformer connected plasma (TCP) reactor, the induction coil 80 is a "spiral" coil or "disc" coil that communicates with the plasma processing zone 15 from above. The design and implementation of an Inductively Connected Plasma (ICP) source, or a Transformer Connected Plasma (TCP) source, is well known to those skilled in the art.

Alternatively, an electron cyclotron resonator (ECR) can be used to form the plasma. In yet another embodiment, the plasma can be formed by the ejection of the Helikon wave. In yet another embodiment, the plasma can be formed as the surface waves are propagated. Each of the above plasma sources is well known to those skilled in the art.

In the following discussion, a method of removing a mask layer or residue from a substrate or both using a plasma processing apparatus is described. The plasma processing apparatus includes various components such as those described in Figures 2 through 6 and combinations thereof.

In one embodiment, the removing step includes forming a plasma formed from a process gas comprising carbon dioxide. In another embodiment, the process gas further comprises a passivating gas, such as a hydrocarbon gas (C _x H _y ). For example, a processing parameter space comprises: a process chamber pressure of from about 20 to about 1000 mTorr; a range of CO ₂ process gas flow, from about 50 to about 1000 sccm; a range of C _x H _y process gas flow as needed, from about 50 Up to about 1000 sccm; the upper electrode (e.g., component 70 in Figure 5) RF bias range, from about 500 to about 2000 W; and the lower electrode (e.g., component 20 in Figure 5) RF bias range, 10 to about 500 W. Also, the upper electrode bias frequency can range from about 0.1 MHz to about 200 MHz, such as about 60 MHz. In addition, the lower electrode bias frequency can range from about 0.1 MHz to about 100 MHz, such as about 2 MHz.

In another alternative embodiment, RF power is supplied to the upper electrode instead of the lower electrode. In another alternative embodiment, RF power is supplied to the lower electrode instead of the upper electrode.

Typically, the time of removal of the mask layer or residue, or both, can be determined using a design of experiment (DOE) method. However, endpoint detection can also be used to make decisions. One possible method of endpoint detection is to monitor a portion of the spectrum emitted by the plasma region, which indicates when a change in plasma chemistry occurs due to the fact that the photoresist is substantially removed from the substrate and is underneath The material film is obtained by contact. For example, it is pointed out that a portion of the spectrum of such changes contains a wavelength of 482.5 nm (CO) and can be measured by optical emission spectroscopy (OES). After the emission level corresponding to the monitored wavelength crosses a specified threshold (eg, drops to substantially zero or increases above a particular level), an end point can be considered completed. Other wavelengths that provide endpoint information can also be used. Moreover, the etching time can be extended to include an over-ashing period, wherein the over-ashing period constitutes an etching process A portion of the time between the start of the detection and the associated endpoint detection (ie 1 to 100%).

In one example, a method of removing a mask layer and post-etching residues is described after the dry etch process to transfer the pattern to the underlying dielectric layer. The dielectric layer contains an ultra low dielectric constant (ultra low k or ULK) material. For example, the ULK material comprises a porous SiCOH film formed by plasma enhanced chemical vapor deposition (PECVD) processing. The removal step can be performed using a plasma processing apparatus as described in FIG. However, the methods discussed are not limited to the scope of this illustrative description.

As mentioned above, the inventors have found that the use of CO ₂ in the plasma ashing process can reduce the damage to the dielectric compared to the O ₂ ashing process. The inventors have further discovered that certain embodiments of varying the ashing process can reduce the critical dimension deviation of the etched features in the dielectric. Table 1 describes the critical dimension deviation (CD deviation, measured in nanometers, nm) of the etched features in the ULK film after various dry plasma ashing treatments (presented in Table 1) and HF wet cleaning. For features that are densely located within the ULK film (dense ULK CD deviation) and features that are not densely located within the ULK film (isolated (Iso) ULK CD offset), provide the top (top), feature at the feature The CD depth of the middle depth (middle) and the bottom (bottom) of the feature.

As illustrated in Table 1, a change in the processing of the dry plasma ashing step is performed, which includes varying the process pressure, bias RF power, and process gas composition. CD offset from examination of Table 1, the increase in the flow rate of CO ₂ can lead to the dense and isolated features (see Test samples C0 and C4) of the marginal reduction. In addition, a reduction in process pressure can result in a marginal reduction in the CD deviation of the dense and discrete features (see test samples C1 and C2). In addition, an increase in bias RF power can result in a marginal reduction in the CD deviation of the dense and discrete features (see test samples C1 and C4). CD departing from further examination of Table 1, the added passivating gas may lead to dense and isolated features (see Test Sample C1 and C8) in marginal reduction of the passivating gas contained in the process gas composition was added to CH _4. For test sample C5, 90% of the total process gas flow is directed over the substrate substantially at the central portion of the substrate, while the remaining 10% of the total process gas flow is introduced substantially close to the edge portion of the substrate. In this way, the CD deviation of the dense and discrete features can be further reduced.

Still referring to Table 1, test samples C9 through C12 illustrate the effect of performing a pre-treatment step prior to the dry plasma ashing step. The pretreatment step includes exposing the substrate to a hydrocarbon gas (e.g., CH ₄₎ processing gas plasma formed in the gas before and blunt. The inert gas may comprise an inert gas such as Ar, or it may comprise N ₂ . The use of pre-processing steps affects the marginal reduction in CD deviations of dense and discrete features. For test sample C13, introduction of hydrocarbon gas and blister gas (Ar) was performed during the dry plasma ashing step. The pre-processing step marginally affects the CD deviation following the residue removal step.

Figure 7 depicts a flow diagram of a method of removing residue from a substrate in a plasma processing system, in accordance with an embodiment of the present invention. Step 400 begins the process gas introduced into the plasma processing system of step 410, wherein the process gas comprises carbon dioxide (CO _2). The process gas further comprises a passivation gas. For example, the passivation gas comprises a hydrocarbon gas (C _x H _y ), wherein x, y represents an integer greater than or equal to one. The hydrocarbon gas (C _x H _y ) may comprise more than one of C ₂ H ₄ , CH ₄ , C ₂ H ₂ , C ₂ H ₆ , C ₃ H ₄ , C ₃ H ₆ , C ₃ H ₈ , C ₄ H ₆ C ₄ H ₈ , C ₄ H ₁₀ , C ₅ H ₈ , C ₅ H ₁₀ , C ₆ H ₆ , C ₆ H ₁₀ or C ₆ H ₁₂ , or two or more of the above. Alternatively, the process gas further comprises an inert gas such as an inert gas (ie, He, Ne, Ar, Kr, Xe, Rn). Or even more, the processing gas further contains O ₂ , CO, NO, NO ₂ or N ₂ O or a combination of two or more of the above.

At 420, a plasma is formed from the process gas using one of the systems of Figures 2 through 6 and combinations thereof in a plasma processing system.

In 430, the substrate comprising the residue is exposed to a plasma formed in 420, including but not limited to a residue of the photoresist layer or photoresist layer, an ARC layer, or a post-etch residue. After the first period of time, step 400 ends. The first period of time during which the substrate having the photoresist layer is exposed to the plasma can generally be specified by the time required to ash the photoresist layer. Usually, the time required to remove the residue is predetermined. Alternatively, the time period can be further expanded via the second period of time or the over-ashing period. As noted above, the over-ashing time can include a portion of the time, such as 1 to 100% of the first period of time, and the over-ashing period can include an extension of the ashing beyond the endpoint detection.

According to another embodiment, a pre-processing step may be added prior to the plasma ashing process described in steps 410-430. A pre-treatment step can be utilized to passivate the various surfaces prior to performing a plasma ashing process to remove any residual masking layers and/or other residues.

In accordance with another embodiment of the present invention, FIG. 8 depicts a method of forming features in a dielectric layer on a substrate in a plasma processing system. The method is illustrated in flow chart 500, which begins with a step 510 of forming a dielectric layer on a substrate. The dielectric layer comprises an oxide layer, such as hafnium oxide (SiO ₂ ), and may be formed by a variety of processes including chemical vapor deposition (CVD). Alternatively, the dielectric layer having a dielectric constant smaller than the standard value of the dielectric constant of SiO _2, which is approximately 4 (e.g., the range of the dielectric constant of silicon dioxide thermally from about 3.8 to about 3.9). More specifically, the dielectric layer can have a dielectric constant of less than about 3.0 or a dielectric constant ranging from about 1.6 to about 2.7.

Alternatively, the dielectric layer can have the characteristics of a low dielectric constant (or low k) dielectric film. The dielectric layer comprises at least one of an organic, inorganic, and inorganic-organic hybrid material. Additionally, the dielectric layer can be porous or non-porous. For example, the dielectric layer comprises an inorganic, citrate-based material deposited using CVD techniques, such as oxidized organodecane (or organic decane). Examples of such films are sold comprising Applied Materials Co., Ltd. Black Diamond ^TM CVD organic silicate glass (OSG) Coral ^TM CVD film membrane, or sold in the Novellus Systems. Meanwhile, the porous dielectric film comprising a single-phase material, such as silicon oxide-based matrix, having interrupted during the curing process of the CH ₃ bond, Bineng create small voids (or pores). Further, the porous dielectric film contains a two-phase material such as a ruthenium oxide-based substrate having fine pores of an organic material such as a pore-forming material, which is evaporated during the curing process. Alternatively, the dielectric film comprises an inorganic, citrate-based material deposited using SOD technology, such as hydrogen sesquioxane (HSQ) or methyl sesquiterpene oxide (MSQ). Examples of such films include FOx HSQ sold by Dow Corning, XLK porous HSQ sold by Dow Corning, and JSR LKD-5109 sold by JSR Microelectronics. Alternatively, the dielectric film comprises an organic material deposited using SOD technology. Examples of such films are sold comprising the Dow Chemical SiLK-I, SiLK-J, SiLK-H, SiLK-D porous SiLK semiconductor dielectric resin, and sold by Honeywell of FLARE ^TM and Nano-glass.

At 520, a patterned mask layer, such as a patterned photoresist layer, is formed over the substrate. The mask layer comprises a single layer or a plurality of layers. For example, the mask layer includes one or more soft mask layers and one or more hard mask layers as desired. For example, a photoresist layer can be formed using conventional techniques such as photoresist spin coating systems. A pattern can be formed in the photoresist film by using conventional techniques such as a stepper microlithography system and a developing solvent.

In 530, the mask layer pattern is transferred to the dielectric layer, and features can be formed in the dielectric layer. Pattern transfer is accomplished using a dry etch technique in which an etch process is performed in the plasma processing system. For example, when etching an oxidized dielectric film such as yttrium oxide, cerium oxide, or the like, or when etching an inorganic low-k dielectric film such as oxidized organic decane, the etching gas composition usually contains a fluorocarbon-based chemical substance, such as At least one of C ₄ F ₈ , C ₅ F ₈ , C ₃ F ₆ , C ₄ F ₆ , CF ₄ or the like, or a fluorocarbon-based chemical substance or a combination thereof, and at least one of an ablative gas, oxygen and CO. Further, for example, when etching an organic low-k dielectric film, the etching gas composition usually includes at least one of a nitrogen-containing gas and a hydrogen-containing gas. Techniques for selectively etching dielectric films as described above are well known to those skilled in the art of dielectric etching processes.

At 540, the mask layer pattern, or residual photoresist or post-etch residue, etc., is removed. The removal of the mask layer is performed by exposing the substrate to a plasma formed by a process gas containing CO ₂ . The process gas further contains a passivation gas. For example, the passivation gas may comprise a hydrocarbon gas (C _x H _y ), wherein x, y represents an integer greater than or equal to one. The hydrocarbon gas (C _x H _y ) may comprise more than one of C ₂ H ₄ , CH ₄ , C ₂ H ₂ , C ₂ H ₆ , C ₃ H ₄ , C ₃ H ₆ , C ₃ H ₈ , C ₄ H ₆ C ₄ H ₈ , C ₄ H ₁₀ , C ₅ H ₈ , C ₅ H ₁₀ , C ₆ H ₆ , C ₆ H ₁₀ or C ₆ H ₁₂ , or two or more of the above. Alternatively, the process gas further comprises an inert gas such as an inert gas (ie, He, Ne, Ar, Kr, Xe, Rn). Or even more, the processing gas further contains O ₂ , CO, NO, NO ₂ or N ₂ O or a combination of two or more of the above.

In the plasma processing system, a plasma is formed from the process gas using any of the systems described in Figures 2 through 6, and the substrate comprising the mask layer is exposed to the formed plasma. The period of time during which the substrate having the photoresist is exposed to the plasma can generally be specified by the time required to remove the photoresist. Usually, the time required to remove the photoresist layer is predetermined. However, the time period can be further expanded via the second period of time or the over-ashing period. As noted above, the over-ashing time can include a portion of the time, such as from 1 to 100% of the time period, and the over-ashing period can include an increase in ashing beyond the endpoint detection.

In one embodiment, transferring the photoresist pattern to the dielectric layer and removing the photoresist system are performed in the same plasma processing system. In another embodiment, transferring the photoresist pattern to the dielectric layer and removing the photoresist system are performed in different plasma processing systems.

According to another embodiment, a pre-processing may precede the plasma ashing process described in step 540. Prior to performing the plasma ashing process, a pre-treatment process can be utilized to passivate the various surfaces of the surface comprising the dielectric layer, and any remaining mask layers and/or other residues can be removed. A pre-treatment process can be utilized to passivate the sidewalls of the features formed in the dielectric layer to avoid deviations in the critical dimension (CD) of the features during the plasma ashing process. For example, the pretreatment process can include exposing the mask layer and the dielectric layer to a plasma formed by the pretreatment process gas, the pretreatment process gas comprising one or more hydrocarbon gases and optionally one or more blunt gases, such as Inert gas or nitrogen.

According to yet another embodiment, during the plasma ashing process, the plasma ashing process described in step 540 is adjusted to reduce the CD deviation of features formed in the dielectric layer. For example, the flow rate of the process gas flowing to a region substantially above the central portion of the substrate may vary with respect to the flow rate of the process gas flowing substantially over the portion of the periphery of the substrate.

While the invention has been described with respect to the embodiments of the present invention, it is to be understood by those skilled in the art possible. Accordingly, it is intended that all such modifications as fall within the scope of the invention.

1‧‧‧Plastic Processing System

1a‧‧‧Plastic processing system

1b‧‧‧Plastic Processing System

1c‧‧‧ Plasma Processing System

1d‧‧‧Plastic Processing System

2‧‧‧ pattern

3‧‧‧ mask

4‧‧‧film

5‧‧‧Substrate

6‧‧‧Characteristic Department

10‧‧‧ Plasma processing room

12‧‧‧Diagnostic system

14‧‧‧ Controller

15‧‧‧Processing area

20‧‧‧Substrate support

25‧‧‧Substrate

30‧‧‧Vacuum pumping system

40‧‧‧RF generator

50‧‧‧ impedance matching network

60‧‧‧ Magnetic field system

70‧‧‧ upper electrode

72‧‧‧RF generator

74‧‧‧ impedance matching network

80‧‧‧Induction coil

82‧‧‧RF generator

84‧‧‧ impedance matching network

400‧‧‧ steps

410‧‧‧Steps

420‧‧ steps

430‧‧ steps

500‧‧‧flow chart

510‧‧ steps

520‧‧‧Steps

530‧‧‧Steps

540‧‧‧Steps

1A, 1B, and 1C show another schematic view of a typical pattern etching process for a film; FIG. 2 shows a simplified schematic view of a plasma processing system in accordance with an embodiment of the present invention; In another embodiment, FIG. 3 shows a schematic diagram of a plasma processing system; FIG. 4 shows a schematic view of a plasma processing system according to another embodiment of the present invention; FIG. 5 shows an electric power according to another embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS In accordance with another embodiment of the present invention, FIG. 6 shows a schematic diagram of a plasma processing system; FIG. 7 depicts a mask removal on a substrate in a plasma processing system, in accordance with an embodiment of the present invention. A method of masking; and in accordance with another embodiment of the present invention, FIG. 8 depicts a method of etching a film on a substrate.

1‧‧‧Plastic Processing System

10‧‧‧ Plasma processing room

12‧‧‧Diagnostic system

14‧‧‧ Controller

Claims (21)

A method for removing residues from a substrate for removing residues from a substrate, comprising: a substrate disposing step, the substrate being disposed in a plasma processing system, the substrate having: a dielectric formed thereon And a mask layer covering the dielectric layer; wherein the mask layer comprises a pattern formed therein, and the dielectric layer includes a feature formed therein by an etching process, the etching Processing for transferring the pattern in the mask layer to the dielectric layer; a pre-processing step of pre-treating the mask layer prior to introducing a process gas comprising carbon dioxide (CO ₂ ), wherein the pre-treatment comprises : introducing a pretreatment treatment gas comprising a hydrocarbon gas having a chemical formula C _x H _y , wherein x and y are integers; wherein the pretreatment gas is processed from the pretreatment gas Forming a pre-treatment plasma; and exposing the mask layer and the dielectric layer to the pre-treatment plasma; and processing a gas introduction step to introduce a treatment gas containing carbon dioxide (CO ₂ ) into the plasma processing system; Slurry forming step, Plasma processing system, a plasma formed from the processing gas; and a mask layer removing step, the plasma from the substrate using the mask layer is removed. The method of removing residue from a substrate according to claim 1, wherein the processing gas introduction step further comprises introducing a passivation gas having one of the carbon dioxide (CO ₂ ). The method of removing residue from a substrate according to claim 2, wherein the processing gas introduction step further comprises introducing a hydrocarbon gas (C _x H _y ), wherein x and y are integers greater than or equal to one. A method for removing a residue from a substrate according to claim 3, wherein the process gas introduction step comprises introducing C ₂ H ₄ , CH ₄ , C ₂ H ₂ , C ₂ H ₆ , C ₃ H ₄ , C ₃ H ₆ , C ₃ H ₈ , C ₄ H ₆ , C ₄ H ₈ , C ₄ H ₁₀ , C ₅ H ₈ , C ₅ H ₁₀ , C ₆ H ₆ , C ₆ H ₁₀ or C ₆ H ₁₂ , or Combination of the above two or more. The method of removing residue from a substrate according to claim 1, wherein the processing gas introduction step further comprises introducing a blunt gas. The method of removing residue from a substrate according to claim 1, wherein the substrate disposing step comprises disposing a substrate having a low dielectric constant dielectric layer in the plasma processing system. The method for removing a residue from a substrate according to claim 1, wherein the substrate arranging step comprises disposing a substrate having at least one of a porous dielectric layer and a non-porous dielectric layer in the plasma. Processing system. The method for removing a residue from a substrate according to claim 1, wherein the substrate arranging step comprises disposing a substrate having a dielectric layer in the plasma processing system, the dielectric layer comprising an organic material and At least one of an inorganic material. A method for removing a residue from a substrate according to claim 8 wherein the substrate disposing step comprises disposing a substrate having a dielectric layer in the plasma processing system, the dielectric layer comprising an inorganic organic mixture material. A method for removing a residue from a substrate according to claim 8 wherein the substrate disposing step comprises disposing a substrate having a dielectric layer in the plasma processing system, the dielectric layer comprising oxidized organic germane. . A method for removing residues from a substrate, as in claim 8 of the patent application, wherein The substrate disposing step includes disposing a substrate having a dielectric layer in the plasma processing system, the dielectric layer comprising at least one of hydrogen sesquioxane and methyl sesquioxanes. A method for removing a residue from a substrate according to claim 8 wherein the substrate arranging step comprises disposing a substrate having a dielectric layer in the plasma processing system, the dielectric layer comprising a bismuth citrate The material of the Lord. The method for removing a residue from a substrate according to claim 10, wherein the substrate arranging step comprises disposing a substrate having a dielectric layer in the plasma processing system, the dielectric layer comprising a concentrating film, The aggregate film contains bismuth, carbon and oxygen. A method of removing a residue from a substrate according to claim 13 wherein the substrate arranging step comprises disposing a substrate having one of hydrogen in the condensed film. The method for removing a residue from a substrate according to claim 1, wherein the processing gas introduction step further comprises introducing O ₂ , CO, NO, NO ₂ or N ₂ O or a combination of two or more of the above. The method for removing residue from a substrate according to claim 1 of the patent application further comprises: maintaining a pressure of one chamber of the plasma processing system at 80 mT; and connecting 800 W of RF power to the chamber. A method of removing residue from a substrate according to claim 16 wherein the process gas introduction step comprises flowing the process gas into the process chamber at a flow rate of 750 sccm. A method for removing a residue from a substrate according to claim 17, wherein 90% of the total flow rate of the processing gas is introduced substantially to a central portion of the substrate, and the total flow rate of the processing gas is The remaining 10% is introduced into an edge portion that is substantially close to one of the substrates. The method for removing residue from a substrate according to claim 18, further comprising: performing a pretreatment step by introducing a mixture of CH ₄ and Ar into the chamber at a chamber pressure between 10 mT and 50 mT. A plasma processing system for removing photoresist from a substrate, the plasma processing system comprising: a plasma processing chamber for promoting a plasma from a pretreatment process gas and a process gas, a dielectric layer on the substrate removes the photoresist; and a controller coupled to the plasma processing chamber and configured to perform a processing recipe comprising: prior to introducing the processing gas comprising carbon dioxide (CO ₂ ) Pre-treating the photoresist, wherein the pre-treatment comprises: introducing the pre-treatment process gas comprising a hydrocarbon gas and a blunt gas, wherein the hydrocarbon gas has the chemical formula C _x H _y , wherein x and y are integers; In the plasma processing system, a pretreatment plasma is formed from the pretreatment process gas; and the photoresist and the dielectric layer are exposed to the pretreatment plasma; the process gas comprising carbon dioxide (CO ₂ ) is to be used Introducing the plasma processing system; in the plasma processing system, forming a plasma from the processing gas; and removing the photoresist from the substrate using the plasma. The plasma processing system of claim 20, wherein the processing gas further comprises a passivation gas.